Acer Swift 3 SF314-51 not powering up - leds flashing

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

While waiting for a response, I was examining the board and found a split (or cracked capacitor show with microscope) and another photo showing where it is situated.

Do you think this could be my problem?

Tks gentlemen!

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Bump!

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

It could be. Whats the part number of the IC below them,the pins are connected to it . Post a close up photo

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

It's DG414AU FDMF 3035, sorry for the flash in the photo. I think KvnTM called it U8002A in a previous post, which I think he got in the schematics.

Also, I powered the board disconnected (I plugged in the power adpater) and checked voltage on pin 27 of the keyboard connector and I get 3.3V.

Thanks for you input!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

It's DG414AU FDMF 3035, sorry for the flash in the photo. I think KvnTM called it U8002A in a previous post, which I think he got in the schematics.

Also, I powered the board disconnected (I plugged in the power adpater) and checked voltage on pin 27 of the keyboard connector and I get 3.3V.

Thanks for you input!

That cap is definitely bad. Measure resistance across it.
I can't find it nowhere in the schematic but that could be it.

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

@rddube can you see where on the chip the small circle is for pin 1.

https://cdn.badcaps-static.com/pdfs/...9b44550a9a.pdf

https://cdn.badcaps-static.com/pdfs/...a40e178c24.pdf

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

@KvnTM looks like the FDMF3035 and SIC631CD are equivalent parts .

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

@KvnTM looks like the FDMF3035 and SIC631CD are equivalent parts .U8002A,U8003A

I was already wondering about that. The chip on the board doesn't match the schematic.

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

They missed out some pins, 9,10 and 11 are vin ,pin 8 is there.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

That cap is definitely bad. Measure resistance across it.
I can't find it nowhere in the schematic but that could be it.

Measuring resistance yields .580M, but there is another capacitor right beside it. So I checked the board, found an identical chip as shown in photo and it has 2 similar caps also, so I compared both ....getting same resistance value on the other chip caps and same capacitance value also = 410uf.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

@rddube can you see where on the chip the small circle is for pin 1.

https://cdn.badcaps-static.com/pdfs/...9b44550a9a.pdf

https://cdn.badcaps-static.com/pdfs/...a40e178c24.pdf

Hi, you can see pin 1 printed on the silkscreen in the photo, looks like pin 8, 9, 10 & 11 go to those 2 caps, including the cracked one.

[mcplslg123]

Re: Acer Swift 3 not powering up - leds flashing

They missed out some pins, 9,10 and 11 are vin ,pin 8 is there.

There is no mention from pin 9 to 15. Seems like 3-4 pins are tied together and shown as one pin only in schematic.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Why would that cap have cracked this way, is it like an internal explosion? Do you think I should remove it and install a 200uf cap 50v just to test? KvnTM said if I ground pin 27 of the keyboard connector it should start up the board....How can I tell if it started up with nothing attached to it? Don't want to burn the CPU Thank you gentlemen!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Why would that cap have cracked this way, is it like an internal explosion? Do you think I should remove it and install a 200uf cap 50v just to test? KvnTM said if I ground pin 27 of the keyboard connector it should start up the board....How can I tell if it started up with nothing attached to it? Don't want to burn the CPU Thank you gentlemen!

You won't burn the cpu. These new cpus can run quite a lot of time without heatsink on idle. And it will shut off when it gets too hot.

There are probably leds on your board that show you if it turns on or not. You could also measure for cpu vcore. It will be present when the board is on. And yes you should replace that cap. Either it exploded or someone damaged it mechanically which is highly unlikely.

And yes, shorting pin 27 on the connector will turn the board on. Just take a look into the schematic. It is really easy to understand how this works. Theres a pull up resistor which pulls the signal high and the button will pull it down to gnd when you press it.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Thank you KvnTM! Ok, will be going to try to see if it will start. To replace the cap, should I remove both and measure the good one to see the value and try and find a similar value on a scrap board, or just a 200uf electrolytic piggy backed on the damaged one would do the trick just to test? Thanks for you advice!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Thank you KvnTM! Ok, will be going to try to see if it will start. To replace the cap, should I remove both and measure the good one to see the value and try and find a similar value on a scrap board, or just a 200uf electrolytic piggy backed on the damaged one would do the trick just to test? Thanks for you advice!

Use a ceramic cap. And yes measure the good one.
Pretty sure you could find one on another board.

I can't tell what the cap is for since I can't find it in the schematic. So replacing it with the correct type would be the best option.

[piernov]

Re: Acer Swift 3 not powering up - leds flashing

Maybe C8057 or one of its friends. You can leave it off for testing. If it is indeed a cap on +AC_BAT_SYS, if it was shorted there would be no power at all.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Ok, so I removed the cracked cap and the good one beside it. The good one measures 108uf and the bad one 10.1uf....now trying to find a 100uf on one of my scrap boards, but my motherboard scrap boards are all desktop, so the caps are electrolytic. I might have to order a 100uf ceramic, unless 10.1uf is good?

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

CPU VCore Power Stage Chip is U8002A in Schematic => SIC631CD-T1-GE3
CPU VCore Controller is U8000A in Schematic => ISL95859HRTZ

Your VCore circuitry consists of two separate chips. U8002A is the power stage (marked on the photo) which is driven by U8000A.

You have to find the ISL chip on your board. Maybe there's something in the schematic that is printed onto the board. Finding it would be your job

U8002A:
Pin 1 => PWM Input from ISL Chip.
Pin 32 => VIN = Battery/AC Voltage
Pin 3 => VCC = 5V

U8000A:
Pin 40 => Enable Input of the Controller. (this is what piernov was talking about)
Pin 34 => VCC = 5v
Pin 33 => VIN = Battery/AC Voltage

Be really careful to NOT short any pins on those chips!
Power cycle the board while measuring PWM/Enable pins and look for any changes. An oscilloscope would be great if you have one.

Please post a photo of the ISL area to confirm it is the correct one.

Hi KvnTM, I changed the cap and all looks good. Board still doesn't start. Getting ready to do the tests. Just to make sure I understand well, could you explain how I should do the tests? Do I check the chips before power cycling the board to see if they get their voltage? I'm a little confused. Tks!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Hi KvnTM, I changed the cap and all looks good. Board still doesn't start. Getting ready to do the tests. Just to make sure I understand well, could you explain how I should do the tests? Do I check the chips before power cycling the board to see if they get their voltage? I'm a little confused. Tks!

You power cycle the board while measuring to look for any signals.